Six inverters in a 14-SOIC — what the 74AC04 brings to a 5V logic chain
The Texas Instruments SN74AC04D is a hex inverter from the 74AC family, packing six independent NOT gates into a 14-SOIC surface-mount package. Each channel inverts a single input with a propagation delay of 7 ns at 5 V driving a 50 pF load, and each output can source or sink 24 mA — enough to drive standard CMOS inputs or a couple of TTL loads without an extra buffer. The supply range spans 2 V to 6 V, so this part works on 3.3 V or 5 V rails without a separate level translator. Operating temperature covers -40°C to 85°C, suiting it for industrial control, motor-drive interface logic, and outdoor telecom equipment where the ambient can swing.
7 ns propagation delay — timing margin at 5 V
The 7 ns max propagation delay at 5 V and 50 pF load is the headline timing spec. In a 5 V logic chain running at 50–100 MHz, that delay eats into the setup-and-hold budget, so a designer will check it against the clock period and the fan-out. The 74AC family is faster than the 74HC series (typically 10–15 ns at 5 V), which is why the AC variant gets picked when the bus needs tighter timing closure.
24 mA output drive — fan-out and load budgeting
That matters when the inverter feeds multiple CMOS inputs, a small relay coil, or an LED indicator through a series resistor. The 24 mA figure is the same for both high and low states, so the drive is symmetric — useful when the load is a transmission line or a bus with equal pull-up and pull-down requirements. For heavier loads, the total package current limit (not per-pin) becomes the constraint; the datasheet's absolute-maximum table governs that.
Supply range 2 V to 6 V — single-rail flexibility
The 2 V to 6 V supply range means the SN74AC04D operates on a 3.3 V rail, a 5 V rail, or even a 2.5 V rail if the system uses that. No level translator needed when mixing 3.3 V and 5 V domains, as long as the input thresholds align. The low-level input threshold is 0.9 V to 1.65 V, and the high-level threshold is 2.1 V to 3.85 V — these shift with supply voltage, so a 3.3 V output driving a 5 V input may need a pull-up or a translator depending on the noise margin.
Lifecycle and compliance — active, ROHS3, no LTB risk
The SN74AC04D is listed as Active on TI's product status, so there is no last-time-buy or end-of-life notice to plan around. ROHS3 compliant, which covers the current EU RoHS exemption list. The 14-SOIC package is a standard JEDEC outline, widely second-sourced across the 74AC family — if TI supply tightens, a pin-compatible 74AC04 from another manufacturer fits the same footprint.
Package and rework — 14-SOIC, surface-mount friendly
The 14-SOIC package (0.154" body width, 3.90 mm) is a through-hole-friendly surface-mount part — the 1.27 mm pitch is easy to hand-solder or rework with a hot-air station. No thermal pad, so no via-stitch requirement; the part dissipates through the leads into the board copper.